Self-adjusting wearing rings



May 19, 1970. J. KL'VKILBANE 3,512,788

SELF-ADJUSTING WEARING RINGS Filed Nov. 1, 1967 J45 W g M @XX B/MMUnited States Patent 3,512,788 SELF-ADJUSTING WEARING RINGS John K.Kilbane, Wauwatosa, Wis., assignor to Allis- Chalmers ManufacturingCompany, Milwaukee, Wis. Filed Nov. 1, 1967, Ser. No. 679,759 Int. Cl.F16j 9/00; F16k 41/00 US. Cl. 277-25 2 Claims ABSTRACT OF THE DISCLOSUREA self-adjusting wearing ring between a pump impeller and the pumpcasing. The wearing ring is slidably contained in an annular groove inthe peripheral surface of the impeller and forced into sealingengagement with the pump casing due to centrifugal force as the impellerrotates.

This invention relates generally to rotary pumps and more specificallyto a means for providing a seal between the pump impeller and the pumpcasing.

In rotary pumps it is necessary to provide a seal between the rotatingimpeller and the stationary casing so that the fluid passing through thepump will not leak excessively between the impeller and the casing. Thisis usually accomplished by providing a wearing ring in the pump casing.In most cases the wearing ring is rigidly contained in the pump casing.In some cases means to manually adjust the wearing ring are provided sothat adequate sealing can be maintained as wear takes place between therelatively rotating parts. However, even with an adjustable wearingring, it is difficult to determine when adjustment should be made and atwhat frequency.

It is therefore the general object of this invention to provide a sealbetween the pump impeller and the pump casing which is self-adjusting.

A more specific object of the subject invention is to provide a sealelement in the pump impeller which is forced radially due to centrifugalaction, into sealing engagement with a sealing surface on the pumpcasing.

These and other objects of the subject invention will become more fullyapparent as the following description is read in light of the attacheddrawing wherein:

FIG. 1 is a cross sectional view of a pump incorporating this invention;

FIG. 2 is an exploded view of a portion of FIG. 1 showing the invention;and

FIG. 3 shows a suggested type of sealing element.

Referring more specifically to the drawing and particularly FIG. 1, theinvention is shown for purposes of illustration in connection with acentrifugal pump generally designated 6. The pump has a casing 7 havingan axial inlet 8 and a radially spaced discharge 9. .The casing 7 isprovided with a rear cover plate 11 which combines with the rest of thecasing to define an impeller chamber 12. A suitable impeller 13 ismounted on one end of a drive shaft 14 and positioned within theimpeller chamber 12 with the other end of the shaft extending through anopening in the rear cover plate 11. For purposes of illustration, theimpeller shown herein is of the closed type and has both a front andrear shroud plate numbered and 15 respectively. The shaft is adapted tobe driven by a suitable source of power such as an electric motor (notshown).

A stufling box 16 with an annular cavity surrounding the shaft 14 isformed in the rear cover plate 11. The stuffing box is filled with anysuitable packing material and the outboard end of the stufling box isclosed oif by an annular gland 17. v

The impeller 13 has an intake 18 aligned with the inlet 8 and a set ofblades 19 that propel fluid radially outward into the discharge volute21. In the preferred em- 3,512,788 Patented May 19, 1970 bodiment, theimpeller 13 has a front hub 22 and a rear hub 23. The rear hub 23 isrigidly connected to the shaft 14. In the preferred embodiment shownherein for purposes of illustration, the front hub 22 is an extension ofthe front shroud plate 10.

The front hub 22 has an annular groove 24 therein with an open endfacing radially outward from the rotational axis of the impeller. Asealing surface 26 in the form of a ringed insert is rigidly connectedto the pump casing 7 and positioned concentric with the groove 24. Asealing element 27 is slidably contained within the groove 24. Thesealing element 27 may be composed of two half sections as shown in FIG.3. This is to permit radial movernent of the sealing element in thegroove 24 due to centrifugal force as the impeller 13 rotates. Grooves25 are provided on the interior surface of the ring 27. In order toprohibit relative rotation between the ring 27 and the impeller 13antirotation pins 29 are provided in the front hub 22 and extend intothe grooves. The grooves are open on the radially inner end to permitradial movement of the ring. With the sealing element 27 in the groove24, upon rotation of the impeller the two half sections of the sealingelement will move outward into sealing engagement with the insert 26.With this arrangement, an adequate seal is provided between the impellerand the pump casing which does not require periodic adjustment.

There is contact along the surface 28 between the sealing element 27 andthe front wall of the groove 24. This contact is caused by the pressuredifferential between opposite sides of the sealing element. The interiorof the pump is exposed to the higher pressure of the fluid WhlCh hasbeen expelled into the volute after passing through the pump impeller.This higher pressure fluid therefore forces the sealing element 24 intocontact with the forward surface of the groove 24 providing a seal alongthe surface 28.

From the above it can be seen that an extremely inexpensiveself-adjusting seal has been provided bet-ween the rotating impeller andstationary casing of a rotary pump. Although only one embodiment hasbeen herern shown and described, other embodiments will be ap parent tothose skilled in the art after reading this description and it isintended that all such embodiments as come within a reasonableinterpretation of the appended claims be covered.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. In a rotary pump, the combination of a casing defining a pumpingchamber, an impeller including a hub rotatably supported in the pumpingchamber and a sealing device between the impeller and casing for sealinghigh pressure fluid in the pumping chamber comprising: an annular groovein the outer surface of said hub having radially extending side wallsand an open end extending radially from the rotational axis of theimpeller; an annular sealing surface on the interior of said casingconcentric with said groove and radially spaced therefrom; a sealingring composed of at least two arcuate segments slidably contained insaid groove and moved radially outwardly by centrifugal force intosealing engagement with said sealing surface upon rotation of saidimpeller, the width of said sealing ring being slightly less than thewidth of said groove whereby said ring is urged axially into sealingengagement with the side wall of said groove remote from said pumpingchamber by the action of the high pressure fluid in the pumping chamberupon rotation of the impeller; and means associated with said ring andsaid hub prohibiting relative rotational movement therebetween whilepermitting both radial and axial movement of said ring relative to saidhub.

2. The sealing device set forth in claim 1 wherein said pump is of thecentrifugal type, said impeller is of 4 the closed 'type having both afront and rear shroud plate 2,570,427 10/ 1951 Chillson et al 27781 Xand said groove is in said front shroud plate. 2,943,463 7/1960 Shipley277-25 X References Cited SAMUEL ROTHBERG, Primary Examiner UNITEDSTATES PATENTS 5 US. Cl. X.R.

1,715,944 6/1929 Oliver. 2,162,218 6/1939 Hill 27768 X 27732, 132, 174;103-103, 111

